Background: Besides anatomically-based radiodiagnostics, functional imaging may be used for characterizing soft tissue sarcomas (STS). This study evaluates positron emission tomography (PET) with three different radiotracers (fluorine-18 deoxyglucose [FDG], carbon-11 aminoisobutyric acid [AIB] and oxygen-15-labeled water [O15-water]) for imaging STS and the detection of local recurrence.
Patients and methods: 21 patients presented with 9 primary STS, 5 recurrent STS and 10 lesions suspicious for local recurrence (radiological tomography). Standardized uptake values (SUV) were calculated in tumor and normal tissues (muscle/blood vessels). Surgery with pathological examination or follow-up data were referred to as control criteria.
Results: All tracers accumulated in STS with no difference between primary and locally recurrent tumors. The uptake in STS was increased compared to muscle (FDG, P < 0.0001; AIB, P = 0.0039; O15-water, P = 0.002) and to blood vessels for FDG (P < 0.0001) as well as AIB (P = 0.0038). Of 10 patients with suspected recurrence, 6 presented neither PET criteria for recurrence nor local failure in the specimens or during follow-up, while 4 cases with positive PET scans were ultimately diagnosed with local failure.
Conclusion: Besides FDG, AIB and O15-water were shown to accumulate in primary and recurrent STS of different histologic type. A precise differentiation from normal muscle was found for all tracers. FDG and AIB differentiated viable tumor from blood vessels. PET using FDG, AIB and O15-water is suitable for functional imaging of STS and the detection of sarcoma recurrence.